Patent Grant
8637357
The present invention relates generally to semiconductor devices, and more particularly a structure for and a method of manufacturing a complementary metal oxide semiconductor (CMOS) transistor device.
Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment, as examples. Semiconductor devices are typically fabricated by sequentially depositing insulating (or dielectric) layers, conductive layers and semiconductive layers of material over a semiconductor substrate, and patterning the various layers using lithography to form circuit components and elements thereon.
A transistor is an element that is utilized extensively in semiconductor devices. There may be millions of transistors on a single integrated circuit (IC), for example. A common type of transistor used in semiconductor device fabrication is a metal oxide semiconductor field effect transistor (MOSFET).
Early MOSFET processes used one type of doping to create either positive or negative channel transistors. More recent designs, referred to as complementary MOS (CMOS) devices, use both positive and negative channel devices in complementary configurations. While this requires more manufacturing steps and more transistors, CMOS devices are advantageous because they utilize less power, and the devices may be made smaller and faster.
The gate dielectric for MOSFET devices has in the past typically comprised silicon dioxide, which has a dielectric constant of about 3.9. However, as devices are scaled down in size, using silicon dioxide for a gate dielectric becomes a problem because of gate leakage current, which can degrade device performance. Therefore, there is a trend in the industry towards the development of the use of high dielectric constant (k) materials for use as the gate dielectric in MOSFET devices. The term “high k materials” as used herein refers to a dielectric material having a dielectric constant of about 4.0 or greater.
High k gate dielectric development has been identified as one of the future challenges in the 2002 edition of International Technology Roadmap for Semiconductors (ITRS), incorporated herein by reference, which identifies the technological challenges and needs facing the semiconductor industry over the next 15 years. For low power logic (for portable electronic applications, for example), it is important to use devices having low leakage current, in order to extend battery life. Gate leakage current must be controlled in low power applications, as well as sub-threshold leakage, junction leakage, and band-to-band tunneling.
To fully realize the benefits of transistor scaling, the gate oxide thickness needs to be scaled down to less than 2 nm. However, the resulting gate leakage current makes the use of such thin oxides impractical in many device applications where low standby power consumption is required. For this reason, the gate oxide dielectric material will eventually be replaced by an alternative dielectric material that has a higher dielectric constant. However, device performance using high k dielectric materials tends to suffer from trapped charge in the dielectric layer, which deteriorates the mobility, making the drive current lower than in transistors having silicon dioxide gate oxides, thus reducing the speed and performance of transistors having high k gate dielectric materials.
Another problem with using a high-k dielectric material as the gate electrode of a CMOS transistor is referred to in the art as a “Fermi-pinning” effect, which occurs at the interface of the gate electrode and gate dielectric material. Fermi-pinning is a problem that occurs in CMOS devices having both poly-silicon and metal gates. The Fermi-pinning effect causes a threshold voltage shift and low mobility, due to the increased charge caused by the Fermi-pinning effect. Fermi-pinning causes an assymmetric turn-on threshold voltage Vt for the two transistors of a CMOS device, which is undesirable.
In prior art CMOS transistor designs, the gate dielectric material for the CMOS was typically SiO2 and the gate electrode was polysilicon. A symmetric threshold voltage Vt for the PMOS device and the NMOS device of a prior art CMOS device was easily achievable using SiO2 as a gate dielectric material. For the PMOS device, the gate electrode was P-type, which was typically achieved by using polysilicon doped with B as the PMOS gate electrode material, as examples. For the NMOS device, the gate electrode was N-type, which was typically achieved by using polysilicon doped with P as the NMOS gate electrode material, as examples.
However, when attempts are made to use hafnium-based dielectric materials, a high k dielectric material, for the gate dielectric material of a CMOS device, problems arise. For the NMOS device, polysilicon doped with P may be used as the material for the gate electrode, and an N-type gate is achievable, which is desired. However, for the PMOS device, if polysilicon doped with B, for example, is used for the gate electrode material, the hafnium-based gate electrode material interacts with adjacent materials, caused by Fermi-pinning, resulting in an N-type gate, which is ineffective for the PMOS device. An N-type gate on the PMOS transistor is undesirable: the PMOS device gate should be P-type to optimize the CMOS device performance and achieve a symmetric Vtp and Vtn. Thus, a CMOS device having an N-type gate electrode for the PMOS transistor has an asymmetric Vtn and Vtp, due to the Fermi-pinning effect of the high k dielectric material. Efforts have been made to improve the quality of high-k dielectric films and resolve the Fermi-pinning problems, but the efforts have resulted in little success.
In electronics, the “work function” is the energy (usually measured in electron volts) needed to remove an electron from the Fermi level to a point an infinite distance away outside the surface. Work function is a material property of any material, whether the material is a conductor, semiconductor, or dielectric. The work function of a metal is fixed and cannot be changed unless the material composition is changed, for example. The work function of a semiconductor can be changed by doping the semiconductor material. For example, undoped polysilicon has a work function of about 4.5 eV, whereas polysilicon doped with boron has a work function of about 5.0 eV. The work function of a semiconductor or conductor directly affects the threshold voltage of a transistor when the material is used as a gate electrode.
In prior art CMOS devices utilizing SiO2 as the gate dielectric material, the work function can be changed or tuned by doping the polysilicon used for the gate electrode material. However, the Fermi-pinning caused by the use of high k gate dielectric materials as the gate dielectric pins or fixes the work function, so that doping the polysilicon gate material does not change the work function. Thus, a symmetric Vt for the NMOS and PMOS transistors of a CMOS device having a high k material for the gate dielectric cannot be achieved by doping polysilicon gate material, as in SiO2 gate dielectric CMOS devices.
Thus, what is needed in the art is a CMOS transistor device design and method of manufacturing thereof that has a high-k gate dielectric and a symmetric Vt for the p channel metal oxide semiconductor (PMOS) and n channel metal oxide semiconductor (NMOS) transistors of the CMOS device.
These and other problems are generally solved or circumvented, and technical advantages are generally achieved, by preferred embodiments of the present invention which provide a CMOS transistor device design and method of manufacture thereof having a substantially symmetric threshold voltage Vt for the PMOS and NMOS transistors. A different gate dielectric material is used for the PMOS transistor than for the NMOS transistor. Advantageously, the novel invention uses the Fermi-pinning effect to achieve a symmetric Vt, by disposing a Fermi-pinning material immediately beneath the gate of the PMOS transistor.
In accordance with a preferred embodiment of the present invention, a semiconductor device includes a workpiece, a first transistor formed in a first region of the workpiece, and a second transistor formed in a second region of the workpiece proximate the first region of the workpiece. The first transistor includes a first source and a first drain disposed in the workpiece, a first channel region disposed between the first source and the first drain, a first gate dielectric disposed over the first channel region, the first gate dielectric comprising a first material, and a first gate disposed over the first gate dielectric. The second transistor includes a second source and a second drain disposed in the workpiece, a second channel region disposed between the second source and the second drain, a second gate dielectric disposed over the second channel region, the second gate dielectric comprising a second material, and a second gate disposed over the second gate dielectric, wherein the second material is different from the first material.
In accordance with another preferred embodiment of the present invention, a method of manufacturing a semiconductor device includes providing a workpiece, the workpiece comprising a first region and a second region, forming a first gate dielectric material over the second region of the workpiece, forming a first gate material over the first gate dielectric material, forming a second gate dielectric material over the first region of the workpiece, the second gate dielectric material comprising a different material than the first gate dielectric material, and forming a second gate material over the second gate dielectric material. The method includes patterning the first gate material, the second gate material, the first gate dielectric material and the second gate dielectric material, wherein the first gate material comprises a first gate of a first transistor, wherein the first gate dielectric material comprises a first gate dielectric of the first transistor, wherein the second gate material comprises a second gate of a second transistor, and wherein the second gate dielectric material comprises a second gate dielectric of the second transistor.
Advantages of preferred embodiments of the present invention include providing a method of fabricating a CMOS device and structure thereof wherein the PMOS transistor and NMOS transistor have a symmetric Vt. The threshold voltage Vt is decreased compared to prior art CMOS devices, and the flat band voltage is easier to tune. Embodiments of the invention may utilize high-k dielectric materials as the gate dielectric, using polysilicon, metal or FUSI gate electrodes. The metal gate electrodes may comprise either single metal or dual-work function metals, e.g., the gate electrode for the PMOS and NMOS transistor may be the same material or different materials.
The foregoing has outlined rather broadly the features and technical advantages of embodiments of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of embodiments of the invention will be described hereinafter, which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the preferred embodiments and are not necessarily drawn to scale.
The making and using of the presently preferred embodiments are discussed in detail below. It should be appreciated, however, that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the invention, and do not limit the scope of the invention.
High-k gate dielectrics generally yield orders of magnitude lower gate leakage current than SiO2 gate dielectrics with the same effective oxide thickness (EOT). For low standby power (LSTP) applications, the use of a high-k material for a gate dielectric is a potential solution in the roadmap for the advanced technology nodes. Using high-k materials for gate dielectrics in CMOS devices has resulted in good EOT, lower gate leakage (Jg), mobility and hysteresis parameters, but the devices suffer from lack of Vt controllability. In order to make high-k materials as gate dielectrics useful in CMOS applications, it is desirable that the CMOS device should be manufactured such that Vtn and Vtp are symmetrical; e.g., Vtn=0.3 V and Vtp=−0.3 V, as examples.
Attempts to use a high-k dielectric material such as HfO2 have been problematic. In particular, attempts have been made to use HfO2, which is a high-k dielectric material having a dielectric constant of about 25, as the gate dielectric for both the PMOS and NMOS FETs of a CMOS device. The work function of a polysilicon gate using a HfO2 gate dielectric has been found to be pinned, as a result of Fermi-pinning, at a point close to the conduction band of polysilicon, causing the polysilicon gate to function as N-type polysilicon, even for the polysilicon gate doped with p-type dopant, for the PMOS device. Therefore, the threshold voltage Vtp of the PMOS device was much higher than expected; e.g., Vtp was −1.2 V while Vtn was 0.4 V, which is very asymmetric. The Fermi-pinning effect is suspected to be related to the Hf—Si bond at the gate electrode-gate dielectric interface, which is almost impossible to avoid with a polysilicon-HfO2 gate stack structure. Therefore, the Fermi-pinning effect makes the use of polysilicon as a gate electrode incompatible with Hf-based high-k gate dielectric materials in CMOS devices. Fully silicided polysilicon (FUSI) gates have also exhibited Fermi-pinning effects and are undesirable for use as gate electrode materials when a high-k dielectric such as hafnium is used for a gate dielectric.
Embodiments of the present invention derive technical advantages by disposing a thin layer of a Fermi-pinning material such as Al2O3 adjacent and abutting a gate electrode of a PMOS device, disposed over a high-k dielectric material such as HfO2, while using single layer of high-k dielectric material as the gate dielectric for the NMOS device. By doing so, polysilicon or FUSI may be used as the gate electrode while still achieving a symmetric Vtp and Vtn for the CMOS device. In the PMOS portion, a polysilicon-Al2O3 interface sets the work function in the p-type regime, and in the NMOS portion, a polysilicon-Hf interface sets the work function in the n-type regime.
The present invention will be described with respect to preferred embodiments in a specific context, namely a CMOS transistor. Embodiments of the present invention may also be applied, however, to other semiconductor device applications where two or more transistors are required. Note that in the drawings shown, only one PMOS device and one NMOS device are shown; however, there may be many PMOS and NMOS devices formed during each of the manufacturing processes described herein.
The workpiece 102 includes a first region 104 and a second region 106. The first region 104 comprises a region where a first transistor comprising a PMOS device or PMOSFET, as examples, will be formed. The second region 106 comprises a region where a second transistor comprising an NMOS device or NMOSFET will be formed, as examples. The PMOS device and NMOS device are not shown in
The first region 104 and the second region 106 may be separated by an optional shallow trench isolation (STI) region 108 formed in the workpiece 102, as shown. The first region 104 may be lightly doped with N type dopants, and the second region 106 may be lightly doped with P type dopants. In general, the workpiece 102 is doped with N or P type dopants depending on whether the junctions of the transistor to be formed will be P or N type, respectively.
The workpiece 102 is preferably cleaned using a pre-gate clean process to remove any contaminant or native oxide from the top surface of the workpiece 102. The pre-gate treatment may comprise a HF, HCl or ozone based cleaning treatment, as examples, although the pre-gate treatment may alternatively comprise other chemistries.
A hard mask 112 is deposited over the workpiece 102, as shown in
A first layer of photoresist 118 is deposited over the second layer 116 of the hard mask 112, as shown in
The first layer of photoresist 118 is used to pattern at least the second layer 116 of the hard mask 112, as shown in
A first gate dielectric material 120 is deposited over the patterned hard mask 112 and exposed portions of the workpiece 102, as shown in
A first gate material 122 is deposited over the first gate dielectric material 120, also shown in
The first gate material 122 may comprise a plurality of stacked gate materials, such as a metal underlayer with a polysilicon cap layer disposed over the metal underlayer, or a combination of a plurality of metal layers that form a gate electrode stack. The first gate material 122 may be deposited using CVD, PVD, ALD, or other deposition techniques, as examples. The first gate material 122 preferably comprises a thickness of about 1500 Å, although alternatively, the first gate material 122 may comprise about 1000 Å to about 2000 Å, or other dimensions, for example.
If the first gate material 122 comprises a semiconductive material, such as in the embodiment shown in
A second layer of photoresist 124 is deposited over the first gate material 122, as shown in
The second layer of photoresist 124 is used as a mask to pattern the first gate material 122 and the first gate dielectric material 120, and to remove the hard mask 112 from the first region 104 of the workpiece 102, as shown in
Next, a second gate dielectric material 126 is deposited over exposed portions of the workpiece 102 in the first region 104 and over the patterned first gate material 122 and first gate dielectric material 120 in the second region 106, as shown in
The second gate dielectric material 126 may comprise a single layer of material, or alternatively, the second gate dielectric material 126 may comprise two or more layers, wherein the top layer comprises a Fermi-pinning material, which will be described further herein with reference to
Next, a second gate material 128 is deposited over the second gate dielectric material 126, also shown in
If the second gate material 128 comprises a semiconductive material, such as in the embodiment shown in
A third layer of photoresist 130 is deposited over the second gate material 128, as shown in
The third layer of photoresist 130 is then used as a mask to pattern the second gate material 128 and second gate dielectric material 126, as shown in
Any excess second gate material 128 and second gate dielectric material 126 (e.g., as shown at peak 132) may be removed from over the optional STI region 108 proximate the interface of the first region 104 and second region 106 using a chemical-mechanical polish (CMP) process or an etch process, for example (not shown), leaving the structure shown in
Preferably using a single lithography step, e.g., using a single layer of photoresist and using a single mask to pattern the photoresist, the first gate material 120, the first gate dielectric material 122, the second gate material 126, and the second gate dielectric material 128 are simultaneously patterned with a desired pattern for a CMOS device, leaving the structure shown in
Referring again to
Manufacturing of the CMOS device 100 is then continued to complete the fabrication of the CMOS device 100. For example, spacers 134 may be formed on the sidewalls of the gate electrode materials 128 and 122, and on the sidewalls of the gate dielectric materials 126 and 120, forming the structure shown in
One or more insulating materials (not shown) may be deposited over the PMOS transistor 136 and NMOS transistor 138, and contacts may be formed in the insulating materials in order to make electrical contact with the gates, sources and/or drains. Additional metallization and insulating layers may be formed and patterned over the top surface of the insulating material and contacts. A passivation layer (not shown) may be deposited over the insulating layers or the PMOS transistor 136 and NMOS transistor 138. Bond pads (also not shown) may be formed over contacts, and the semiconductor device 100 may then be singulated or separated into individual die. The bond pads may be connected to leads of an integrated circuit package (not shown) or other die, for example, in order to provide electrical contact to the transistors 136 and 138 of the semiconductor device 100.
Thus, a novel semiconductor CMOS device 100 comprising a PMOS transistor 136 and an NMOS transistor 138 is formed, as shown in
The gate and gate dielectric materials for either the PMOS transistor 136 or the NMOS transistor 138 may be deposited first, in accordance with embodiments of the present invention. For example, in the embodiment described herein, the NMOS transistor 138 gate dielectric and gate materials are deposited first. Alternatively, the PMOS transistor 136 gate dielectric and gate materials may be deposited first.
Another preferred embodiment of the present invention is shown in
In this embodiment, the PMOS device 204 is shown in the right side of the figure, and the NMOS device 206 is shown on the left side. The gate dielectric GD1 in this embodiment comprises at least two insulating layers: a first insulating layer 250 and a second insulating layer 252 disposed over the first insulating layer 250. The first insulating layer 250 preferably comprises a high-k dielectric material, and may comprise HfO2, HfSiOX, ZrO2, ZrSiOX, Ta2O5, La2O3, nitrides thereof, SixNy, SiON, SiO2, or combinations thereof, as examples, although alternatively, the first insulating layer 250 may comprise other high k insulating materials or other dielectric materials. The first insulating layer 250 preferably comprises a thickness of about 80 Angstroms or less, for example. The second insulating layer 250 preferably comprises about 10 to 60 Angstroms of a Fermi-pinning material. For example, the second insulating layer 250 preferably comprises an aluminum-containing material such as aluminum oxide (AlxOy or Al2O3) or nitrides thereof, such as AlxOyN1-x-y, as examples, although alternatively, the second insulating layer 250 may comprise other materials that induce Fermi-pinning of the gate dielectric GD1 to the gate electrode G1 of the PMOS device 236. The second insulating layer 250 may be deposited or may be formed by implanting a Fermi-pinning material such as aluminum, for example.
This embodiment also shows other optional elements that may be included in the CMOS device 200. Before forming spacers 234 over the sidewalls of the gate dielectric GD1 and GD2 and gates G1 and G2, an optional thin insulator 248 may be formed over the top surface of the sources S1 and S2 and drains D1 and D2, the sidewalls of the gate dielectrics GD1 and GD2, and gates G1 and G2, as shown. The spacers 234 are then formed over the thin insulator 248. The thin insulator 248 may comprise an oxide, and the spacers 234 may comprise a nitride, although alternatively, other materials may be used for the thin insulator 248 and the spacers 234, for example.
The sources S1 and S2 or the drains D1 and D2, or the gates G1 and G2, may include an optional silicide material 244 and 246, respectively, formed at a top surface thereof (often referred to as a salicide because the formation of the silicide may be self-aligning). The silicide 244 and 246 may comprise about 100 Å to 300 Å of TiSix, CoSix, or NiSix, although the silicide 244 and 246 may alternatively comprise other materials and thicknesses, as examples. The sources S1 and S2 and drains D1 and D2 may include lightly doped areas and deeper implantation regions, as shown.
The novel CMOS device of embodiments of the present invention described herein having a PMOS transistor and an NMOS transistor that have gate dielectrics comprising different materials may be manufactured using other methods. Two examples of such other methods are shown
For example, a hard mask 312 may be formed over the second gate material 328. A layer of photoresist 318 may be deposited over the hard mask 312, and the photoresist 318 may be removed from over the second region 306 using lithography techniques, for example, as shown in
Next, the first gate dielectric material 320 and the first gate material 322 are deposited over the second region 306 of the workpiece 302 and over the second gate material 328 over the first region 304 of the workpiece 302, as shown in
While a vertical portion 362 of the first gate dielectric material 320 formed on the sidewall of the second gate material 322 is left remaining in the structure shown in
The embodiment shown in
The gate dielectric material 466 preferably comprises HfO2, HfSiOX, Al2O3, ZrO2, ZrSiOX, Ta2O5, La2O3, nitrides thereof, SixNy, SiON, SiO2, or combinations thereof, for example, although alternatively, the gate dielectric material 466 may comprise other materials. The gate dielectric material 466 may comprise a thickness of a few hundred Angstroms or less, for example. The gate material 468 may comprise a semiconductor material or a metal, for example. For example, the gate material 468 may comprise polysilicon, other semiconductor materials, TiN, HfN, TaN, W, Al, Ru, RuTa, TaSiN, NiSix, CoSix, TiSix, Ir, Y, Pt, Ti, PtTi, Pd, Re, Rh, (borides, phosphides, or antimonides of Ti), Hf, Zr, TiAlN, Mo, MoN, ZrSiN, ZrN, HfN, HfSiN, WN, Ni, Pr, VN, TiW, a fully silicided gate material (FUSI), other metals, and/or combinations thereof, as examples.
In this embodiment, in the first region 404 where a PMOS transistor will be formed, a Fermi-pinning material 464 is implanted. Preferably, the Fermi-pinning material 464 is implanted in the first region 404 but not in the second region 406, as shown. For example, the gate material 468 may be covered with photoresist 424 or an insulating material during the implantation process, as shown. Implanting the Fermi-pinning material 464 may comprise implanting aluminum, for example, although alternatively, the Fermi-pinning 464 may comprise other Fermi-pinning materials.
Preferably, the Fermi-pinning material 464 is implanted into at least the conductive layer 468 over the first region 404 of the workpiece 402, as shown. For example, the Fermi-pinning material 464 is preferably also implanted into a top surface 470 of the insulating layer 466.
Because the Fermi-pinning material 464 is implanted into the first region 404 and not the second region 406, the gate material and gate dielectric material for the first region 404 and second region 406 are now advantageously different, producing the novel CMOS device having different gate dielectric materials and symmetric Vt for a PMOS transistor and NMOS transistor, as shown in
Note that optionally, the gate material 468 in the first region 404 may be doped with a P-type dopant while the second region 406 is masked. Similarly, and the gate material 468 in the second region 406 may optionally be doped with an N-type dopant 472 while the first region 404 is masked, as shown in
The structure shown in
The embodiment shown in
Advantages of embodiments of the invention include providing methods of fabricating a CMOS device 100, 200, 300, 400 and structures thereof wherein the PMOS transistor 136, 236 and the NMOS transistor 138, 238 have a substantially symmetric Vt. For example, Vtn may be about +0.2 to +5 V, and Vtp may be the substantially the same negative value, e.g., about −0.2 to −5 V. The threshold voltages Vt may alternatively comprise other voltage levels, for example. Work function symmetry is achieved by using a different dielectric material GD1 and GD2 for the PMOS transistor 136/236 and the NMOS transistor 138/238, respectively. The threshold voltage Vt is decreased compared to prior art CMOS devices, and the flat band voltage is easier to tune. Embodiments of the invention may utilize high-k dielectric materials as the gate dielectric GD1/GD2, using polysilicon, metal or FUSI gate electrodes G1/G2. The metal gate electrodes G1/G2 may comprise either single metal or dual-work function metals, e.g., the gate electrode G1/G2 for the PMOS and NMOS transistors may be the same material or different materials. In one embodiment, wherein the top layer of the gate dielectric of the PMOS transistor 136/236 comprises an aluminum-containing material, the fact that Si—Al pins to p-type and Si—Hf pins to n-type is utilized, to take advantage of the Fermi-pinning effect rather than trying to solve the Fermi-pinning effect or work around it by changing the material of the gate electrode.
Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. For example, it will be readily understood by those skilled in the art that many of the features, functions, processes, and materials described herein may be varied while remaining within the scope of the present invention. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
This is a divisional application of U.S. application Ser. No. 10/870,616, entitled “CMOS Transistor With Dual High-k Gate Dielectric and Method of Manufacture Thereof,” which was filed on Jun. 17, 2004 and is incorporated herein by reference. This application relates to the following and commonly assigned patent application: Ser. No. 13/444,742, filed Apr. 11, 2012, entitled “CMOS Transistor With Dual High-k Gate Dielectric,” which application is hereby incorporated herein by reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4432035 | Hsieh et al. | Feb 1984 | A |
| 4990974 | Vinal | Feb 1991 | A |
| 5041885 | Gualandris et al. | Aug 1991 | A |
| 5053349 | Matsuoka | Oct 1991 | A |
| 5066995 | Young et al. | Nov 1991 | A |
| 5108935 | Rodder | Apr 1992 | A |
| 5162263 | Kunishima et al. | Nov 1992 | A |
| 5321287 | Uemura et al. | Jun 1994 | A |
| 5352631 | Sitaram et al. | Oct 1994 | A |
| 5763922 | Chau | Jun 1998 | A |
| 5780330 | Choi | Jul 1998 | A |
| 5994747 | Wu | Nov 1999 | A |
| 6020243 | Wallace et al. | Feb 2000 | A |
| 6027961 | Maiti et al. | Feb 2000 | A |
| 6033944 | Shida | Mar 2000 | A |
| 6048769 | Chau | Apr 2000 | A |
| 6084280 | Gardner et al. | Jul 2000 | A |
| 6124171 | Arghavani et al. | Sep 2000 | A |
| 6159782 | Xiang et al. | Dec 2000 | A |
| 6159810 | Yang | Dec 2000 | A |
| 6171910 | Hobbs et al. | Jan 2001 | B1 |
| 6184072 | Kaushik et al. | Feb 2001 | B1 |
| 6225163 | Bergemont | May 2001 | B1 |
| 6291867 | Wallace et al. | Sep 2001 | B1 |
| 6337248 | Imai | Jan 2002 | B1 |
| 6348390 | Wu | Feb 2002 | B1 |
| 6373111 | Zheng et al. | Apr 2002 | B1 |
| 6410967 | Hause et al. | Jun 2002 | B1 |
| 6426534 | Look et al. | Jul 2002 | B1 |
| 6444555 | Ibok | Sep 2002 | B2 |
| 6448127 | Xiang et al. | Sep 2002 | B1 |
| 6475908 | Lin et al. | Nov 2002 | B1 |
| 6492217 | Bai et al. | Dec 2002 | B1 |
| 6528858 | Yu et al. | Mar 2003 | B1 |
| 6563178 | Moriwaki et al. | May 2003 | B2 |
| 6563183 | En et al. | May 2003 | B1 |
| 6586296 | Watt | Jul 2003 | B1 |
| 6621114 | Kim et al. | Sep 2003 | B1 |
| 6656764 | Wang et al. | Dec 2003 | B1 |
| 6693333 | Yu | Feb 2004 | B1 |
| 6716685 | Lahaug | Apr 2004 | B2 |
| 6720221 | Ahn et al. | Apr 2004 | B1 |
| 6737313 | Marsh et al. | May 2004 | B1 |
| 6740944 | McElheny et al. | May 2004 | B1 |
| 6747318 | Kapre et al. | Jun 2004 | B1 |
| 6763822 | Styles | Jul 2004 | B1 |
| 6812542 | Kohyama | Nov 2004 | B2 |
| 6852645 | Colombo et al. | Feb 2005 | B2 |
| 6855605 | Jurczak et al. | Feb 2005 | B2 |
| 6873003 | Casarotto et al. | Mar 2005 | B2 |
| 6890807 | Chau et al. | May 2005 | B2 |
| 6897095 | Adetutu et al. | May 2005 | B1 |
| 6921691 | Li et al. | Jul 2005 | B1 |
| 6936882 | Ahmed et al. | Aug 2005 | B1 |
| 7060568 | Metz et al. | Jun 2006 | B2 |
| 7091568 | Hegde et al. | Aug 2006 | B2 |
| 7348284 | Doyle et al. | Mar 2008 | B2 |
| 7361958 | Brask et al. | Apr 2008 | B2 |
| 20010012653 | Tsukamoto | Aug 2001 | A1 |
| 20020005556 | Cartier et al. | Jan 2002 | A1 |
| 20020053711 | Chau et al. | May 2002 | A1 |
| 20020090773 | Bojarczuk, Jr. et al. | Jul 2002 | A1 |
| 20020098649 | Chien et al. | Jul 2002 | A1 |
| 20020135030 | Horikawa | Sep 2002 | A1 |
| 20020135048 | Ahn et al. | Sep 2002 | A1 |
| 20020151125 | Kim et al. | Oct 2002 | A1 |
| 20020153573 | Mogami | Oct 2002 | A1 |
| 20030057432 | Gardner et al. | Mar 2003 | A1 |
| 20030099766 | Jurczak et al. | May 2003 | A1 |
| 20030104663 | Visokay et al. | Jun 2003 | A1 |
| 20030116804 | Visokay et al. | Jun 2003 | A1 |
| 20030119292 | Lee et al. | Jun 2003 | A1 |
| 20030137017 | Hisamoto et al. | Jul 2003 | A1 |
| 20030141560 | Sun | Jul 2003 | A1 |
| 20030151560 | Kienzle et al. | Aug 2003 | A1 |
| 20030203560 | Ryu et al. | Oct 2003 | A1 |
| 20030219953 | Mayuzumi | Nov 2003 | A1 |
| 20040000695 | Matsuo | Jan 2004 | A1 |
| 20040005749 | Choi et al. | Jan 2004 | A1 |
| 20040009675 | Eissa et al. | Jan 2004 | A1 |
| 20040023462 | Rotondaro et al. | Feb 2004 | A1 |
| 20040094758 | Usuda et al. | May 2004 | A1 |
| 20040113211 | Hung et al. | Jun 2004 | A1 |
| 20040132271 | Ang et al. | Jul 2004 | A1 |
| 20040171222 | Gao et al. | Sep 2004 | A1 |
| 20040180487 | Eppich et al. | Sep 2004 | A1 |
| 20040217429 | Lin et al. | Nov 2004 | A1 |
| 20040242021 | Kraus et al. | Dec 2004 | A1 |
| 20050035345 | Lin et al. | Feb 2005 | A1 |
| 20050064663 | Saito | Mar 2005 | A1 |
| 20050098839 | Lee et al. | May 2005 | A1 |
| 20050101159 | Droopad | May 2005 | A1 |
| 20050139926 | Shimizu et al. | Jun 2005 | A1 |
| 20050224897 | Chen et al. | Oct 2005 | A1 |
| 20050245019 | Luo et al. | Nov 2005 | A1 |
| 20050280104 | Li | Dec 2005 | A1 |
| 20060003507 | Jung et al. | Jan 2006 | A1 |
| 20060017112 | Wang et al. | Jan 2006 | A1 |
| 20060038236 | Yamamoto | Feb 2006 | A1 |
| 20060118879 | Li | Jun 2006 | A1 |
| 20060125018 | Lee et al. | Jun 2006 | A1 |
| 20060131652 | Li | Jun 2006 | A1 |
| 20060141729 | Wang et al. | Jun 2006 | A1 |
| 20060211195 | Luan | Sep 2006 | A1 |
| 20060223335 | Mathew et al. | Oct 2006 | A1 |
| 20060275976 | Wang | Dec 2006 | A1 |
| 20060292773 | Goolsby et al. | Dec 2006 | A1 |
| 20070018245 | Jeng | Jan 2007 | A1 |
| 20070020903 | Takehara et al. | Jan 2007 | A1 |
| 20070034945 | Bohr et al. | Feb 2007 | A1 |
| 20080191286 | Chang et al. | Aug 2008 | A1 |
| Number | Date | Country |
|---|---|---|
| 1298722 | Apr 2003 | EP |
| 1388889 | Feb 2004 | EP |
| 1531496 | May 2005 | EP |
| 2000-031296 | Jan 2000 | JP |
| 2000-058668 | Feb 2000 | JP |
| 2001-217321 | Aug 2001 | JP |
| 2002-118175 | Apr 2002 | JP |
| 2002-151598 | May 2002 | JP |
| 2003-273350 | Sep 2003 | JP |
| 2004-221596 | Aug 2004 | JP |
| 2004-260165 | Sep 2004 | JP |
| 2004-289061 | Oct 2004 | JP |
| 2004-356472 | Dec 2004 | JP |
| 2005-268553 | Sep 2005 | JP |
| WO 0166832 | Sep 2001 | WO |
| WO 2004095556 | Nov 2004 | WO |
| WO 2005114718 | Dec 2005 | WO |
| WO 2006061371 | Jun 2006 | WO |
| WO 2006067107 | Jun 2006 | WO |
| Entry |
|---|
| Aoyama, T., et al., “Proposal of New HfSiON CMOS Fabrication Process (HAMDAMA) for Low Standby Power Device,” IEEE International Electron Devices Meeting, Dec. 13-15, 2004, pp. 95-98. |
| Cho, Byung-Jin, “HfSi Gate Electrode With Tunable Work Function for Advanced CMOS Devices,” National University of Singapore Engineering Research, vol. 19, No. 2, Jun. 2004, 2 pages. |
| Choi, K., et al., “Growth Mechanism of TiN Film on Dielectric Films and the Effects on the Work Function,” Thin Solid Films, vol. 486, Issues 1-2, Aug. 22, 2005, pp. 141-144. |
| “Front End Processes,” International Technology Roadmap for Semiconductors (ITRS), 2002 ITRS Update, http://www.itrs.net/Links/2002Update/2002Update—FEP.pdf, 2002, pp. 45-62. |
| “Front End Processes,” International Technology Roadmap for Semiconductors (ITRS), 2003 Edition, http://www.itrs.net/Links/2003ITRS/FEP2003.pdf, 2003, pp. 23-25. |
| Gannavaram, Shyam, et al., “Low Temperature (≦ 800° C.) Recessed Junction Selective Silicon-Germanium Source/Drain Technology for sub-70nm CMOS,” IEEE International Electron Devices Meeting, 2000, pp. 437-440. |
| Gao, Wei, et al., “Stacked Metal Layers as Gates for MOSFET Threshold Voltage Control,” Mat. Res. Soc. Symp. Proc., vol. 765, 2003, pp. 3-8. |
| Guha, S., et al., “Atomic Beam Deposition of Lanthanum- and Yttrium-Based Oxide Thin Films for Gate Dielectrics,” Applied Physics Letters, vol. 77, No. 17, Oct. 23, 2000, pp. 2710-2712. |
| Ha, Daewon, “Molybdenum-Gate HfO2 CMOS FinFET Technology,” IEEE International Electron Devices Meeting, Dec. 13-15, 2004, pp. 643-646. |
| “High K Dielectric Materials”, Tutorial Materials for Thin Films / Microelectronics, Sigma-Aldrich, http://www.sigmaaldrich.com/Area—of—Interest/Organic—Inorganic—Chemistry/Materials—Science/Thin—Films—Microelectronics/Tutorial/Dielectric—Materials.html, printed on Jun. 9, 2004, 3 pages. |
| Hobbs, C., et al., “Fermi Level Pinning at the PolySi/Metal Oxide Interface,” Symposium on VLSI Technology Digest of Technical Papers, 2003, pp. 9-10. |
| Hobbs, Christopher C., et al., “Fermi-Level Pinning at the Polysilicon/Metal Oxide Interface—Part I,” IEEE Transactions on Electron Devices, vol. 51, No. 6, Jun. 2004, pp. 971-977. |
| Huang, Feng-Jung, et al., “Schottky-Clamped NMOS Transistors Implemented in a Conventional 0.8-μm CMOS Process,” IEEE Electron Device Letters, vol. 19, No. 9, Sep. 1998, pp. 326-328. |
| Kedzierski, Jakub, et al., “Fabrication of Metal Gated FinFETs Through Complete Gate Silicidation with Ni,” IEEE Transactions on Electron Devices, vol. 51, No. 12, Dec. 2004, pp. 2115-2120. |
| Kedzierski, Jakub, et al., “Metal-Gate FinFET and Fully-Depleted SOI Devices Using Total Gate Silicidation,” International Electron Devices Meeting, 2002, pp. 247-250. |
| Li, Hong-Jyh, et al., “Dual High-K Gate Dielectric with Poly Gate Electrode: HfSiON on nMOS and AI2O3 Capping Layer on pMOS,” IEEE Electron Device Letters, vol. 26, No. 7, Jul. 2005, pp. 441-444. |
| Li, Tzung-Lin, et al., “Continuous and Precise Work Function Adjustment for Integratable Dual Metal Gate CMOS Technology Using Hf-Mo Binary Alloys,” IEEE Transactions on Electronic Devices, vol. 52, No. 6, Jun. 2005, pp. 1172-1179. |
| Lin, Ronald, et al., “An Adjustable Work Function Technology Using Mo Gate for CMOS Devices,” IEEE Electron Device Letters, vol. 23, No. 1, Jan. 2002, pp. 49-51. |
| Muller, Richard S., et al., “Device Electronics for Integrated Circuits,” Second Edition, John Wiley & Sons, 1986, pp. 380-385 and 398-399. |
| Park, D.G., et al., “Thermally Robust Dual-Work Function ALD-MNx MOSFETs Using Conventional CMOS Process Flow,” Symposium on VLSI Technology Digest of Technical Papers, 2004, pp. 186-187. |
| Polishchuk, Igor, et al., “Dual Work Function Metal Gate CMOS Transistors Fabricated by Ni-Ti Interdiffusion,” Conf. Symp. Proc, Berkeley Electrical Engineering and Computer Sciences, Feb. 7, 2005, pp. 411-414. |
| Polishchuk, Igor, et al., “Polycrystalline Silicon/Metal Stacked Gate for Threshold Voltage Control in Metal—Oxide—Semiconductor Field-Effect Transistors,” Applied Physics Letters, vol. 76, No. 14, Apr. 3, 2000, pp. 1938-1940. |
| Samavedam, S.B., et al., “Dual-Metal Gate CMOS with HfO2 Gate Dielectric,” IEEE International Electron Devices Meeting, Dec. 8-11, 2002, pp. 433-436. |
| Samavedam, S.B., et al., “Evaluation of Candidate Metals for Dual-Metal Gate CMOS with HfO2 Gate Dielectric,” Mat. Res. Soc. Symp. Proc., vol. 716, 2002, pp. 85-90. |
| Samavedam, S.B., et al., “Fermi Level Pinning with Sub-Monolayer MeOx and Metal Gates,” IEEE International Electron Device Meeting, Dec. 8-10, 2003, pp. 13.1.1-13.1.4. |
| Wakabayashi, Hitoshi, et al., “A Dual-Metal Gate CMOS Technology Using Nitrogen-Concentration-Controlled TiNx Film,” IEEE Transactions on Electron Devices, vol. 48, No. 10, Oct. 2001, pp. 2363-2369. |
| Wolf, S., et al., “Silicon Processing for the VLSI Era, vol. 1—Process Technology,” Second Edition, Lattice Press, Oct. 1999, pp. 338 and 526. |
| Wolf, S., “Silicon Processing for the VLSI Era, vol. 2—Process Integration,” Fifth Edition, Lattice Press, Mar. 1990, pp. 432-441. |
| Yeo, Yee-Chia, et al., “Dual-Metal Gate CMOS Technology with Ultrathin Silicon Nitride Gate Dielectric,” IEEE Electron Device Letters, vol. 22, No. 5, May 2001, pp. 227-229. |
| Number | Date | Country | |
|---|---|---|---|
| 20120193725 A1 | Aug 2012 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10870616 | Jun 2004 | US |
| Child | 13444752 | US |
